1. Field of the Invention
The present invention relates to a wireless power transmission method for preventing frequency interference, and more particularly to a wireless power transmitter and a wireless power transmission method for preventing frequency interference that flexibly controls an operation of the wireless power transmitter in order to avoid signal interference and collision between different apparatuses using frequencies adjacent to a frequency band of a power signal transmitted from the wireless power transmitter.
2. Description of the Related Art
In general, a wireless power transmission system is used as a technology for transmitting power between apparatuses spaced apart from each other by using an induced electromotive force mechanism. The wireless power transmission system enables power transmission between apparatuses placed at separated positions by using a predetermined range of frequency (in general, a frequency in the range of 100 to 210 Khz) and since the wireless power transmission system transmits power by using a wireless signal, if a signal for transmitting power is close to another apparatus using a frequency adjacent to a used frequency band, there is a possibility that malfunction will occur due to frequency interference.
Therefore, in order to avoid frequency inference and collision, a multichannel technology is generally used. However, in the wireless power transmission field, a frequency band which can be practically used is extremely limited. Therefore, there is a disadvantage in that changing and using the frequency variously is limited in order to transmit power wirelessly. Further, if the frequency is changed, power transmission efficiency is consequently varied with the change of the used frequency and the variation range is significantly large, such that it is practically difficult to apply the frequency.
In addition, as another method, a method of shielding electromagnetic waves is used in order to reduce a physical area influenced by the electromagnetic waves for the purpose of preventing frequency interference between different apparatuses. However, this method has a disadvantage in that an additional cost is generated because a shielding member needs to be additionally installed in order to apply an electromagnetic wave shielding structure and if the design of a wireless power transmission structure needs to be changed, this method has another disadvantage in that a shielding structure applied before the design change needs to be redesigned by remeasuring a radiation pattern whenever the design of the wireless power transmitter is changed. Therefore, there is disadvantage in that the method using the electromagnetic wave shielding is complicated to develop and takes a long time to develop.